Racket stringing apparatus



April 12, 1938. c. DOLL RACKET STRINGING APPARATUS Filed May 18, 1937 2 Sheets-Sheet l laura/110e all April l2, 1938. c. DOLL I RACKET STRINGING APPARATUS Filed May 18, v19137 2 Sheets-Sheet 2 Patented Apr. 12, 1938 UNITED STATES PATENT OFFIQE.

RACKET STRINGING APPARATUS Application May 18, 1937, Serial No. 143,355

Claims.

This invention relates to certain new and useful improvements in racket Stringing apparatus.

The primary object of the invention is to provide a racket stringing apparatus of the general I type disclosed in the application for patent led by Laurance C. Doll for improvements in Apparatus for Stringing rackets, filed November 25, 1936, Serial Number 112,807, and more particularly relates to string gripping devices that are 10 manually operated and placed for gripping engagement with the racket strings during the Stringing of the racket for maintaining the strings under the tension imparted thereto during the Stringing operation.

A further object of the invention is to provide racket Stringing apparatus of the foregoing character wherein a pair of string gripping devices in the form of pivoted frames or lever members with a string gripping jaw at each end thereof may be place-d longitudinally or transversely of the racket frame with the gripping jaw at each end of the lever member selectively shifted into string gripping position adjacent the racket frame with means for holding the lever member against pivotal or translating movement while a gripping jaw is engaged with a string.

With the above and other objects in view that will become apparent as the nature of the invention is better understood, the same consists in the novel form, combination or arrangement of parts hereinafter more fully described, shown in the accompanying drawings and claimed.

In the drawings:

Figure 1 is a side elevational view, partly broken away and shown in section of a racket support for racket Stringing apparatus and showing the pivoted frames or lever members. carrying a gripping jaw at each end thereof with the lever members relatively positioned to place a gripping jaw respectively at opposite ends of the two lever members in string gripping position with the other jaw carried by each member lowered to its inactive position, and further showing the pin and rack devices for holding the lever members in adjusted positions;

Figure 2 is a top plan view of the string gripping members removed from the supporting frame;

Figure 3 is a cross-sectional view taken on line 3 3 of Figure 2 with a gripping jaw of each lever member shown by dotted lines in its elevated string gripping position;

Figure 4 is a detail sectional View taken on line 4 4 of Figure 2, showing the bearing for the translating pivotal lever members;

Figure 5 is a detail sectional View taken on line 5 5 of Figure 4, showing the guide connection between the string gripping jaws;

Figure 6 is a detail sectional view taken on line 6 6 of Figure 3; 5

Figure '7 is a fragmentary elevational View of the supporting shaft and bearing for one of the lever members;

Figure 8 is an elevational View of one of the string gripping jaws, showing the file characteristie of the string gripping face of the jaw;

Figure 9 is an edge elevational View of the gripping jaws shown in Figure 8; and

Figure 10 is a diagrammatic plan View of a racket frame with the gripping of the stringsV indicated at certain points.

The support for the racket during the stringing operation is shown. more clearly in Figure l, wherein the reference character I@ designates a base plate adapted for mounting upon a frame 20 carrying the Stringing apparatus for the racket, which structure is not illustrated as the present invention primarily relates to string gripping devices for holding the strings under tension placed thereon. A block support I I rises from each end of the base plate IU and is longitudinally adjustable on the base plate in the guideways I2, the block supports II being retained in adjusted positions by the anchor devices I2a. Another block support I3 rises from each side of the base plate I0 intermediate the ends of the latter and is shiftable transversely of the base plate into transverse guideways I Ll, the block support I3 being suitably ancho-red in adjustable position.

Each of the block supports I I and I3 carries adjustable means for the support of a racket frame and as shown more clearly in Figure 1, each of the block supports has a horizontal opening I4 formed therein for sliding reception of a guide rod I5 that has a perpendicular plate I6 anchored at its lower end as at I'I to the inner end of the guide rod I5. A block I8 is secured as at Ia to the outer face oi the upper end of the plate I5 and extends above the block support and said block I 8 has a key groove therein that opens at the upper end of the block for interlocking reception of a key piece I9 from which racket engaging fingers 20 rise, the racket frame 2| being supported upon the upper ends of the blocks I8 outwardly of the pins 20 and each of the blocks I8 is adapted to be adjusted to move the pinsZll into frictional retaining engagement with the inner face of the racket frame 2I as shown in Figure 1. The adjusting means for each block I8 includes a horizontally disposed threaded shaft 22 resting upon the upper end of the associated block bearing II or I3, the inner end of the threaded shaft 22 being anchored as at 23 to the plate I3 directly beneath the racket frame supporting block I8. The threaded shaft 22 is adapted to be axially shifted for moving the blocks i8 relative to the racket frame 2| by means of a manually operated nut 24 threaded onto the shaft 22 and being substantially swiveled to the associated block support by means of the annular groove 25 in the collar of the nut 24 and into which groove a iinger 26 carried by the block support extends so that upon rotation of the nut 24, the threaded shaft 22 is shifted axially to move the plate I3 carrying the block I8 that supports the racket frame 2l, all of the parts being guided in their movements by the guide rods I5.

With the ratchet frame 2l supported upon the blocks I8 as shown in Figure 1, the same is in position to be strung by appropriate Stringing devices such as disclosed in the application for patent of Laurance C. Doll, hereinbefore identified and during the Stringing of the racket frame the string clamps or grips are adapted to be engaged with certain sections or runs of the string for holding the same under the tension imparted thereto. The string grip and supporting devices therefor include a shaft 21 having a manipulating handle 28 at one end thereof and said shaft is adapted to be selectively mounted in horizontally aligned openings 29 in the opposed sets of block bearings II and I3 directly beneath the bearing openings I4 for the guide rods I5. A pair of lever members is translatably and pivotally supported on the shaft 21 and each lever member 35 carries a string gripping jaw 3l at its outer end.

A bearing is provided for each lever member 3f! and as shown in Figure 4 includes a sleeve 32 slidable on the shaft 21 with a key 33 projecting inwardly of the bore of the sleeve 32 extending into a longitudinal key slot 34 provided in the shaft 21. An annular ange 35 is carried by the sleeve 32 adjacent one end thereof and said sleeve 32 has a lever member 36 supported thereon at one side of the annular ange 35 and as shown in Figures 3 and 4, the lever member 35i includes a pair of spaced parallel rods 36 and 31 connected at their outer ends by a head 38 for the support of a string gripping jaw 3|. The rods 35 and 31 of the lever members 30 when horizontally disposed are freely slidable upon the sleeve 22 but when the lever member 3l) is tilted or pivoted to assume the dotted line positions shown in Figure 3, the upper rack surface 39 of the lower rod 31 moves into engagement with an adjacent pin 40 that projects laterally of the flange 35 at each side of the shaft 21 to hold the lever member 39 against sliding or translating movement upon the bearing sleeve 32 and with the upwardly positioned gripping jaw 3l in position for engagement with the racket string at a point in proximity of the racket frame 2l. The lever members 30 are retained in position on the sleeve 32 by means of the nut 4I threaded onto the threaded end of the sleeve 32 with a washer 42 interposed between the nut 4l and rods 36 and 31 of the lever member 30, the rods 36 and 31 being freely slidable upon the sleeve 32 and only restrained from such movement when the lever member is tilted to cause the rack teeth 39 upon the upper side of the lower bar to be engaged with .a pin 40 carried by the flange 35.

The string gripping jaws 3| are supported on the head 38 at the ends of the lever members 30, each head carrying a gripping jaw that includes a jaw member 43 that is carried by a shank 44 anchored as at 45 to one side of the head 38 with a movable jaw member 46 associated with the fixed jaw member 43. As shown in Figure 2,' the Shanks 44 carrying the gripping jaws at corresponding ends of the lever members 33 are respectively offset towards each other to present the gripping jaws at two corresponding ends of the lever members normally in closer relationship than the gripping jaws at the other two corresponding ends of the lever members. As shown in Figures 4 to 9, the lower straight edge of the movable jaw 46 is provided with three horizontally aligned transversely extending openings 41 that register with corresponding openings 41a in the fixed jaw 43, pins 48 anchored in the end openings 41 of the movable jaw 46 projecting therefrom for guiding reception in the end openings 410. in the fixed jaw. A headed screw 49 passes through the central opening 41a in the fixed jaw and is threaded into the registering central opening 41 in the movable jaw, this arrangement being shown in Figure 5. Opposed sockets 49 and 49a are formed in the inner faces of the jaws 43 and 46 for the reception of a coil spring il that normally tends to separate the jaws. The opposed faces of the upper ends of the jaws 43 and 46 carry file plates 5I to effect proper gripping of the racket strings and the terminal upper horizontal edges of the two jaws 43 and 46 are transversely notched as at 52 to provide clearance for strings extending trans-.

versely of the longitudinal axis of a string gripping jaw, the notches 52 being spaced apart a distance corresponding to the distance between the racket strings. Each of the jaws 43 .and 46 is provided with an aligned transverse opening 53 directly above the socket 49, the opening 53 in the jaw 43 being threaded for engagement by the jaw operating screw 54 that freely extends through the opening 53 in the movable jaw 45, the outer end of the screw 54 carrying a disk head 55 that is movable into engagement with the jaw 46 for moving the same into clamping engagement with the Xed jaw 43, the terminal outer end of the screw 54 outwardly of the disk head 55 carrying an operating handle 56.

The shaft 21 supporting the lever members 38 is illustrated in Figure 1 as mounted in the block support I3 for cooperation with the longitudinal strings of the racket, it being understood that the shaft 21 is also adapted to be positioned in the bearings 23 in the block supports I I for gripping engagement with the transverse strings of the racket. In the Stringing of a racket, the lever members 30 are shifted to the positions shown in Figure 1 and are locked in such positions by the engagement of the rack portion 39 of the lower rod 31 of a lever member engaged with a pin 4i] and when so disposed, the gripping jaw at one end of a lever member is elevated to string gripping position while the jaw member upon the same frame lever member is lowered to its inoperative position, the Stringing of the racket beginning at the median line thereof with the lever members being sequentially moved outwardly or separated from each other on the supporting shaft 21 for gripping engagement with the subsequent string to be extensioned. The Stringing of the racket frame is schematically illustrated in Figure 10, the gripping jaw at one end of a lever member being initially engaged with the string a at the point b while a pulling force is exerted on the string c in the direction of the associated arrow line outwardly of the opposite end of the racket frame. The string gripping jaw of the other lever member is then engaged with the end of the string c at the point d, with the string c being then tensioned between the points b and d. The second pulling strain is placed on the string a outwardly of the bracket frame while the gripping jaw is still engaged with the string -a at the point b and after the string a has been placed under the desired tension, a gripping jaw is engaged with the opposite end of the string a at the point e, the gripping `jaw being disengaged at the point b so that both strings a and b are then fully tensioned between the points b and d. The third pull is exerted upon the string f outwardly of the racket frame and a gripping jaw engaged therewith at the point g, while the fourth pull is exerted upon the string i outwardly of the racket frame and gripping jaw engaged therewith at the point 7c, this operation being continued until the racket frame is completely strung in one direction and after which the gripping jaws are shifted for engagement with the strings that extend transversely of the racket frame 2 l.

From the above detailed description of the invention, it is believed that the construction and operation thereof will at once be apparent and while there is herein shown and described the preferred embodiment of the invention, it is nevertheless to be understood that minor changes may be lmade therein without departing from the spirit and scope of the invention as claimed.

I claim:-

l. In racket Stringing apparatus, a base plate, two pairs of diametrically opposite block supports respectively attached tothe side and end portions of the base plate for the mounting of racket frame supports, means for gripping the racket strings for holding them under tension during the Stringing of the racket frame including a shaft selectively mounted in a pair of diametrically opposite supports, and a pair of elements having translatable pivotal mountings on the shaft intermediate the ends thereof whereby said elements may be moved both longitudinally and laterally of the shaft into string gripping position for gripping engagement with a racket string.

2. In racket Stringing apparatus, a base plate, two pairs of diametrically opposite block supports respectively attached to the side and end portions of the base plate for the mounting of racket frame supports, means for gripping the racket strings for holding them under tension during the Stringing of the racket frame including a shaft selectively mounted in a pair of diametrically opposite supports, and a pair of elements having translatable pivotal mountings on the shaft intermediate the ends thereof whereby Said elements may be moved both longitudinally and laterally of the shaft into string gripping positions and a string gripping jaw at each end of said elements adapted for gripping engagement with a racket string.

3. In racket Stringing apparatus, a base plate, two pairs of diametrically opposite block supports respectively attached to the side and end portions of the base plate for the mounting of racket frame supports, means for gripping the racket strings for holding them under tension during the Stringing of the racket frame including a shaft selectively mounted in a pair of diametrically opposite supports, a pair of elements having translatable pivotal mountings on the shaft intermediate the'ends thereof whereby said elements may be moved both longitudinally and laterally of the shaft into string gripping positions for gripping engagement with a racket string, and cooperating means carried` by said elementsand shaft for holding the elements in shifted positions.

4. In racket Stringing apparatus, a base plate, two pairs of diametrically opposite 'block supports respectively attached to the side and end portions of the base plate for the mounting of racket frame supports, means for gripping the racket strings for holding them under tension during the Stringing of the racket frame including a shaft selectively mounted in a pair of diametrically opposite supports, a pair of elements having translatable and pivotal mountings on the shaft whereby said elements may be moved both longitudinally and' laterally of the shaft into spring gripping positions, a string gripping jaw at each end of Said elements adapted for gripping engagement with a racket string, and cooperating means carried by said elements and shaft for holding the elements in shifted positions.

5. In racket Stringing apparatus, a base plate, two pairs of diametrically opposite block supports respectively attached to the side and end portions of the base plate for themounting of racket frame supports, means for gripping the racket strings for holding them under tension during the Stringing of the racket frame including a shaft selectively mounted in a pair of diametrically opposite supports, a pair of elements having translatable pivotal mountings on the shaft whereby Said elements may be moved both longitudinally and laterally of the shaft into string gripping positions, each element including a lever member having a pair of spaced parallel rods, a head connecting corresponding ends of the rods, a string gripping jaw carried by each head and cooperating means carried by one of said rods and said shaft for holding the elements in shifted positions.

6. In racket Stringing apparatus, a base plate, two pairs of diametrically opposite block supports respectively attached to the side and end portions of the base plate for the mounting of racket frame supports, means for gripping the racket strings for holding them under tension during the Stringing of the racket frame including a shaft selectively mounted in a pair of diametrically opposite supports, a pair of elements having translatable pivotal mountings on the shaft whereby said elements may be moved both longitudinally and-laterally of the Shaft into string gripping positions, each element including a lever member having a pair of spaced parallel rods, a head connecting corresponding ends of the rods, a string gripping jaw carried by each head and cooperating means carried by one of said rods and said shaft for holding the elements in shifted positions including a bearing on the shaft for said element, pins projecting from said bearing at opposite sides of said shaft and rack teeth on the inner Side of one of the rods adapted for engagement with a pin when said element is pivotally moved to place one of the jaws in string gripping position.

7. In racket Stringing apparatus, a base plate, two pairs of diametrically opposite block supports respectively attached to the side and end portions of the base plate for the mounting of racket frame Supports, means for gripping the racket strings for holding them under tension during the stringing of the racket frame including a shaft selectively mounted in a pair of diametrically opposite supports, a pair of elements having translatable pivotal mountings on the shaft whereby said elements may be moved both longitudinally and laterally of the shaft into string gripping positions, a string gripping jaw at each end of said elements for gripping engagement with a racket string, and cooperating means carried by said elements and shaft for holding the elements in shifted positions, each gripping jaw including a jaw member fixed to the pivotal element, a jaw movable relative to the iixed jaw and string engaging iile plates secured to the active faces of the iixed and movable jaws, and both of said jaws of a pivotal clement being normally disposed in a plane below the plane of the racket frame to be strung with the jaws at each end selectively raised into position for string gripping activity.

8. In racket stringing apparatus, a base plate, two pairs of diametrically opposite block supports respectively attached to the side and end portions of the base plate for the mounting of racket frame supports, means for gripping the racket strings for holding them under tension during the stringing of the racket frame including a shaft selectively mounted in a pair of diametrically opposite supports, a pair of elements having translatable pivotal mountings on the shaft whereby said elements may be. moved both longitudinally and laterally of the shaft into string gripping positions and a string gripping jaw at each end of said elements adapted for gripping engagement with a racket string, and cooperating means carried by said elements and shaft for holding the elements in shifted positions, each gripping j-aw including a jaw member fixed to the pivotal element, a jaw movable relative to the fixed jaw, and both of said jaws of a pivotal element being normally disposed in a plane below the plane of the racket frame to be strung with the jaws at each end selectively raised into position for string gripping activity.

9, In racket stringing apparatus, a base plate, two pairs of diametrically opposite block supports respectively attached to the side and end portions of the base plate for the mounting of racket frame supports, means for gripping the racket strings for holding them under tension during the stringing of the racket frame including a shaft selectively mounted in a pair of diametrlcally opposite supports, a pair of elements having translatable pivotal mountings on the shaft whereby said elements may be moved both longitudinally and laterally of the shaft into string gripping positions, a gripping jaw at each end oi said elements for gripping engagement with a racket string, each element including a lever member having a pair of spaced parallel rods, a head connecting corresponding ends of the rods, a string gripping jaw carried by each head and cooperating means carried by one of said rods and said shaft for holding the elements in shifted positions, each gripping jaw including a jaw member iixed to the pivotal element, a jaw movable relative to the fixed jaw and string engaging file plates secured to the active faces of the fixed and movable jaws, and both of said jaws of a pivotal element being normally disposed in a plane below the plane of the racket frame to be strung with the jaws at each end selectively raised into position for string gripping activity.

10. In racket stringing apparatus, a base plate, two pairs of diametrically opposite block Supports respectively attached to the side and end portions of the base plate for the mounting of racket frame supports, means for gripping the racket strings for holding them under tension during the stringing of the racket frame including a shaft selectively mounted in a pair of diametrically opposite supports, a pair of elements having translatable pivotal mountings on the shaft whereby said elements may be moved both longitudinally and laterally of the shaft into string gripping positions, a string gripping jaw at each end of said elements for gripping engagement with a racket string, each element including a lever member having a pair of spaced parallel rods, a head connecting corresponding ends including a bearing on the shaft for said element, pins projecting from said bearing at opposite sides of said shaft and rack teeth on the inner side of one of the rods adapted for engagement with a pin when said element is pivotally moved to place one of the jaws in string gripping position, each gripping jaw including a jaw member iixed to the pivotal element, a jaw movable relative to the fixed jaw and string engaging le plates secured to the active faces of the fixed and movable jaws, and both of said jaws of a pivotal element being normally disposed in a plane below the plane of the racket frame to be strung with the jaws at each end selectively raised into position for string gripping activity.

LAURANCE C. DOLL. 

